Document «tight» in the glossary

Closes #2005, and maybe helps a little bit #1730.

Also learn new words (from previous additions)

Author: JJ

doc/Language/glossary.pod6

@@ -613,7 +613,7 @@ object and also refers to the object itself.
 X<|LHS>
 =head1 LHS
 
-As an acronym left-hand side, it usually refers to the left hand side of an expression, and more specifically to the left-hand side of expresions such as C<$lhs = "this would be the right-hand side">. Since the left hand side of these expressions modify their value, when something behaves as a LHS it means that it can be read and written to.
+As an acronym left-hand side, it usually refers to the left hand side of an expression, and more specifically to the left-hand side of expressions such as C<$lhs = "this would be the right-hand side">. Since the left hand side of these expressions modify their value, when something behaves as a LHS it means that it can be read and written to.
 
 =head1 lvalue
 X<|Value>
@@ -1091,6 +1091,12 @@ X<|Thunk>
 
 A piece of code that isn't immediately executed, but doesn't have an independent scope.
 
+X<|Loose>
+X<|Tight>
+=head1 Tight and loose precedence
+
+In this context, tight or tighter refers to L<precedence rules|https://docs.perl6.org/language/functions#index-entry-is_tighter> and is the opposite of C<looser>. Precedence rules for new terms are always expressed in relationship with other terms, so C<is tighter> implies that operands with that operator will be grouped before operands with the looser operator. Operators with L<tight precedence|https://docs.perl6.org/language/operators#Tight_AND_Precedence> are grouped with priority to others and are generally tighter than most others; loose L<exactly the opposite|https://docs.perl6.org/language/traps#Loose_boolean_operators>, so it is always convenient to be aware of the exact precedence of all operators used in an expression.
+
 =head1 twine
 X<|twine>
 
@@ -1122,7 +1128,7 @@ A L<type object|https://docs.perl6.org/language/classtut#index-entry-type_object
 =head1 value
 X<|value>
 
-A value is what is actually contained in a container such as a variable. Used in expresions such as L<lvalue>, to indicate that that particular container can be assigned to.
+A value is what is actually contained in a container such as a variable. Used in expressions such as L<lvalue>, to indicate that that particular container can be assigned to.
 
 =head1 Value type
 X<|Value type>

xt/words.pws

@@ -1359,3 +1359,8 @@ yyyy
 zef
 zoffixznet
 zwj
+Worthington
+rhs
+lhs
+RHS
+LHS